Consolidated Statements of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of shares of common stock issued under stock option plan	45,289	67,029	227,410
Number of common stock shares purchased	41,915	154,633	60,595
Preferred stock			$ 1.375
Common stock	$ 0.73	$ 0.69	$ 0.65
Common Stock [Member]
Number of shares of common stock issued under stock option plan	45,289	67,029	227,410
Additional Paid-in Capital [Member]
Number of shares of common stock issued under stock option plan	45,289	67,029	227,410
Treasury Stock [Member]
Number of common stock shares purchased	41,915	154,633	60,595